Well, my first thought is that she sounds crazy... but sometimes people act hostile like she did because they are hiding emotions about something else. If it were me, I would be cordial to her, but I wouldn't put forth extra effort to "friend" her. She doesn't know how to communicate very well as evidenced by her not telling you that you offended her several months ago. Find a better friend.

Treat her like a casual acquaintance but don't be friends with her. If she asks you to hang out just say you're busy. Save your friendship for people who don't accuse you of harassment based on a few texts spread out over several weeks.